astcopy.c revision 7c2fbfb345896881c631598ee3852ce9ce33fb07
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2008 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Bell Laboratories
*
* copy from rfd to wfd (with conditional mmap hacks)
*/
#include <ast.h>
#include <ast_mmap.h>
#if _mmap_worthy > 1
#include <ls.h>
#define MAPSIZE (1024*256)
#endif
#undef BUFSIZ
#define BUFSIZ 4096
/*
* copy n bytes from rfd to wfd
* actual byte count returned
* if n<=0 then ``good'' size is used
*/
off_t
astcopy(int rfd, int wfd, off_t n)
{
register off_t c;
#ifdef MAPSIZE
off_t pos;
off_t mapsize;
char* mapbuf;
struct stat st;
#endif
static int bufsiz;
static char* buf;
if (n <= 0 || n >= BUFSIZ * 2)
{
#if MAPSIZE
if (!fstat(rfd, &st) && S_ISREG(st.st_mode) && (pos = lseek(rfd, (off_t)0, 1)) != ((off_t)-1))
{
if (pos >= st.st_size) return(0);
mapsize = st.st_size - pos;
if (mapsize > MAPSIZE) mapsize = (mapsize > n && n > 0) ? n : MAPSIZE;
if (mapsize >= BUFSIZ * 2 && (mapbuf = (char*)mmap(NiL, mapsize, PROT_READ, MAP_SHARED, rfd, pos)) != ((caddr_t)-1))
{
if (write(wfd, mapbuf, mapsize) != mapsize || lseek(rfd, mapsize, 1) == ((off_t)-1)) return(-1);
munmap((caddr_t)mapbuf, mapsize);
return(mapsize);
}
}
#endif
if (n <= 0) n = BUFSIZ;
}
if (n > bufsiz)
{
if (buf) free(buf);
bufsiz = roundof(n, BUFSIZ);
if (!(buf = newof(0, char, bufsiz, 0))) return(-1);
}
if ((c = read(rfd, buf, (size_t)n)) > 0 && write(wfd, buf, (size_t)c) != c) c = -1;
return(c);
}